Technical Field
The present disclosure relates to a circuit board, and an electronic component device.
Related Art
In the related art, an electronic component device is configured by connecting an electronic component such as a semiconductor chip to a circuit board by flip-chip bonding. In such an electronic component device, bump electrodes of electronic component are connected to connection pads of a circuit board by solder, and the spaces between the circuit board and the electronic component are filled with an underfill resin.    [Patent Document 1] Japanese Patent Application Publication No. 2007-103878    [Patent Document 2] Japanese Patent Application Publication No. 2013-118255
As will be described with respect to preliminary technologies, if a temperature cycle test is performed on an electronic component device configured by connecting a semiconductor chip to a circuit board by flip-chip bonding, it is easy for thermal stress to be concentrated on the lower corner portions of connection pads of the circuit board.
For this reason, cracks are generated from the portions of a resin layer contacting the lower corner portions of the connection pads into the connection pads.